1. Technical Field
The present invention relates to an electrooptical apparatus that includes a mirror, a production method for the electrooptical apparatus, and an electronic appliance.
2. Related Art
As electronic appliances, for example, projection type display apparatuses that modulate light emitted from a light source using a plurality of mirrors (micro mirrors) of an electrooptical apparatus called DMD (digital mirror device) and perform magnifying projection of the modulated light using a projection optical system so as to display images on a screen are known. In the electrooptical apparatus used in such an electronic appliance, the mirrors are supported on torsion hinges (twist hinges) via mirror support posts and are electrically connected to the torsion hinges. Besides, the torsion hinges (twist hinges) are supported by substrate-side bias electrodes formed on a substrate with the hinge support posts interposed therebetween, and are also electrically connected to the substrate-side bias electrodes. Therefore, by applying a bias voltage from a substrate-side bias electrode to a corresponding one of the mirrors and applying a drive voltage to an address electrode, the mirror can be driven due to electrostatic force created between the mirror and the address electrode. In a production process for an electrooptical apparatus having such a construction, torsion hinges (twist hinges), mirrors, and the like are formed by using a sacrificial layer made of a resin material.
On another hand, for formation of a mirror support post, JP-A-8-227042 proposes a construction in which a metal layer is formed on a surface of a columnar sacrificial layer left on a torsion hinge (twist hinge).
However, if a mirror support post is formed by stacking a metal layer using a columnar sacrificial layer, there is a risk that a gas may be produced from the sacrificial layer when the temperature of the electrooptical apparatus rises because of emitted light or heat generation of the substrate or the like at the time of operating a drive circuit. Such a gas, if it adheres to the surface (reflecting surface) of a mirror, degrades the reflectance of the mirror, and is therefore not preferable.